Containers and method of manufacture thereof

ABSTRACT

A container comprised of a circular or elliptical wall member, which is bent inwardly at the bottom to form an inwardly directed radial flange, and a bottom disc member, is prescored with a plurality of score lines in the portion of the wall member which forms the flange, so that folds resulting from the bending operation form along the score lines.

United States Patent 72] Inventor Carl R. Peacock [56] References Cited Fulton, N.Y. UNITED STATES PATENTS '2 gm" 1 31 3,039,371 6/1962 Leibreich 229/s.5x 1 3,065,678 11/1962 Armstrong 93/391 3 331 547 7/1967 c3116 229/5 5x [73] Assign Phillips Petroleum company Primary Examiner-David M. Bockenek Attorney-Young and Quigg [54] CONTAINERS AND METHOD OF MANUFACTURE THEREOF w Cmms 9 Drawing Figs ABSTRACT: A container comprised of a circular or elliptical [52] US. Cl 229/5.5, wall member, which is bent inwardly at the bottom to form an 229/35, 93/551, 93/39.l inwardly directed radial flange, and a bottom disc member, is [51] Int. Cl 865d 3/10 prescored with a plurality of score lines in the portion of the [50] Field of Search 229/55, wail member which forms the flange, so that folds resulting from the bending operation form along the score lines.

PATENTEU JUN 8|97l 3583524 SHEEIIUFZ INVENTOR. Y J c. R PEACOCK FIG. .3 BY

A T TORNE VS PATENTED JUN 8 I97! SHEET 2 OF 2 FIG. 8

FIG.

INVENTOR. C R PEACOCK A 7' TORNE VS CONTAINERS AND METHOD OF MANUFACTURE THEREOF This invention relates to a novel container structure and a method of manufacture thereof. In one aspect the invention relates to containers ofsubstantially circular or elliptical cross section wherein a portion of the upstanding wall is bent inwardly to form a flange. In a particular aspect the invention re lates to an improvement in the types of containers illustrated in Isaac L. Wilcox, US. Pat. No. 3,369,726, issued Feb. 20, 1968.

In the past, the inward bending of a portion of an upstanding wall of circular or elliptical cross section to form a flange has resulted in the random formation of fold lines of various thicknesses, angles and spacing. This lack of uniformity not only detracts from the aesthetic value of the container, but can render the container unstable if the container rests on the flange.

In accordance with the invention, it has been discovered that these difficulties can be avoided or at least minimized by prescoring the flange forming portion of the wall member with a plurality of approximately parallel, substantially uniformly spaced scored lines.

Accordingly, it is an object of the invention to provide an improved container and a method of manufacture thereof. Another object of the invention is to provide a simplified method and apparatus for forming the improved container.

Other objects, aspects and advantages of the invention will be apparent from a study of the specification, the drawings and the appended claims to the invention.

In the drawings, FIG. 1 is a plan view of a blank for forming a cylindrical sidewall, FIG. 2 is a cross-sectional view along line 2-2 in FIG. 1, FIG. 3 is an exploded view in perspective of a cylindrical sidewall preform and a circular bottom disc during formation of the container, FIG. 4 is an elevational view of the resulting completed container, FIG. 5 is a bottom view of the container of FIG. 4 in accordance with a presently preferred embodiment of the invention, FIG. 6 is a partial elevational view taken along line 6-6 in FIG. 5, FIG. 7 is a partial elevational view taken along line 7-7 in FIG. 5, and FIGS. 8 and 9 are cross-sectional views of the flanging and sealing dies at the start and completion, respectively, of the operation of forming the bottom structure of FIG. 5.

Referring now to FIG. 1, blank 11 is generally rectangular and has an upper edge 12, a lower edge 13 and side edges 14 and 15. Blank 11 is provided with a plurality of score lines 16 located within the lower marginal area 18 bounded by lower edge 13 and imaginary line 17. Score lines 16 extend generally perpendicularly toward lower edge 13 and are at least approximately uniformly spaced along the extent of lower edge 13. Score lines 16 are inwardly directed indentations in the outer surface of blank 11, as illustrated in FIG. 2.

Blank 11 is bent or convoluted about a mandrel or other forming device to overlap the side margins adjacent edges 14 and as illustrated in FIG. 3. The thus overlapped side margins are bonded to form a cylindrical preform 21. A bottom circular disc 22 is positioned within the hollow of the preform 21 either prior to, during or subsequent to the formation of the preform 21. Disc 22 is positioned adjacent the lower marginal area 18 of the cylindrical preform 21 at a point corresponding substantially to the imaginary line 17 of FIG. 1. The lower marginal area 18 is then bent inwardly towards the axis 23 of the circular cross section of preform 21 and into contact with the enclosed bottom circular disc 22 to thereby form an inwardly directed radial flange 24, as illustrated in FIGS. 5 and 7. While the invention will be described in terms of preform 21 being in the form of a right angle cylinder, it is within the scope of the invention to use preforms which are in the form of a truncated cone with the taper of the wall from the bottom to the top being either inwardly or outwardly with respect to the axis of the cone, as well as in the forms having elliptical cross sections. The term substantially circular," as used herein, includes other continuously inwardly curved forms such as ellipses. Preform 21 can also be formed by other procedures, for example, as a section of a wound tubing. Rolled rim 25 (FIG. 4) can be formed by any conventional method known in the art. The side margin adjacent side edge 14 preferably has notches 26 and 27 cut in the corners thereof to facilitate the rolling of the upper edge of the preform 21 to form the rolled rim 25 and the bending of the lower marginal area 18 to form the inwardly directed flange 24. The container can be closed with any conventional closure known in the art, including a cover of the type illustrated in US. Pat. No. 2,926,8 l 2 or a film of thermoplastic material having a label or other decoration printed thereon.

Referring now to FIGS. 5-9, the presently preferred bottom structure is formed by placing cylindrical preform 21 around mandrel 31 (which may also be the mandrel for forming the flat blank 11 into the cylindrical shape). The lower marginal portion 18 of preform 21 extends beyond the end 33 of mandrel 31. End 33 of mandrel 31 is flat except for a continuous annular ridge 34 disposed at the periphery of end 33. Bottom disc 22 is placed inside portion 18 and against ridge 34. Relative movement between mandrel 31 and cooperating hollow folding sleeve 35 is then effected. The end of sleeve 35 facing end 33 of mandrel 31 has an inwardly curved annular surface or groove 36 in the inner edge thereof. The outer diameter of groove 36 is equal to the outer diameter of cylindrical preform 21. The wall of groove 36 is in the form of an inwardly curved surface which is coaxial with preform 21 on mandrel 31 with the apparent apex of the inwardly curved surface being remote from the preform. The cross section of groove 36 can be in the form ofa arc ofa circle, an elliptical arc, or any other suitable configuration. Sleeve 35 can be provided with sloping surfaces 37, 38 which act as centering means to guide edge 13 of the preform 21 into groove 36. The relative movement of mandrel 31 towards sleeve 35 causes the lower marginal portion 18 of preform 21 to enter groove 36 and thereby effects a simultaneous inwardly bending of the lower marginal area 18 throughout the extent of the lower edge 13 to form flange 24. The inward bending of lower marginal area 18 causes the formation of a fold 40 along each of score lines 16 to accommodate the excessive material in lower marginal area 18 due to the reduction in diameter thereof during the bending operation. After flange 24 has been formed substantially perpendicularly to the axis of the container, a sealing rim 41 positioned within the hollow sleeve 35 is moved against flange 24 to effect the high pressure seal 42 by means of a continuous annular ridge 43.

In a presently preferred embodiment of the invention, blank 11 and bottom circular disc 22 are formed of a suitable material, for example paperboard, having a coating on each side thereof of a synthetic thermoplastic polymeric material, for example, polyethylene or polyvinyl chloride. The bonding of the overlapped margins to each other to form cylindrical preform 21 and the structural bonding of the bottom circular disc 22 to the flange 24 can thus be effected by a thermal bonding of the contacting thermoplastic coatings. While it is presently preferred for both blank 11 and disc 22 to have thermoplastic coatings on both sides, it is also possible to utilize either a blank and/or a disc having a coating on only one side. In such instances it is necessary for at least one of flange 24 and disc 22 to have its coating in the area of contact of flange 24 and disc 22.

The bending of portion 18 by impingement upon the curved surface of groove 36 is sufficient to bring the inner surface of portion 18 into contact with the bottom surface of disc 22 to effect a structural bond, but not necessarily a leakproof seal. Annular ring 43 effects a high pressure crushing of the holds 40 in the annular area 42 to thereby reduce any space between adjacent layers of folds 40 to sufficiently small dimension to be filled with the thermoplastic material. The width or radial dimension, with respect to the axis of preform 21, of ridge 43 is sufficiently narrow with respect to the width of flange 24 to permit a leakproof seal by means of the high pressure crushing of the hold lines in the area 42. Ridge 43 has a smaller diameter, with respect to the axis of preform 21, than ridge 34 but is sufficiently close thereto to force the inner portion of flange 24 and the center portion of disc 22 against the flat face of mandrel 31 as shown in FIG. 9. This coaction of ridges 34 and 43 results in the formation of an upwardly opening continuous annular gutter 46 in disc 22 adjacent the periphery of disc 22 and in the adjacent portion of flange 24. Upwardly opening gutter 46 increases the strength of the bottom construction over that which would be obtained by an L-shaped joint and also serves to provide a peripheral annular foot on which the container can rest when placed on a surface in an upright position despite minor variations in the inner portion of flange 24 or a downward bulge in the center portion of disc 22. The radial dimension, with respect to the axis of preform 21, of gutter 46 is less than the radial dimension of flange 24.

Ram 41 can also be provided with a second annular ridge 48, concentric to but of smaller diameter than ridge 43. Ridge 48 is positioned to effect a crushing of the folds 40 near the inner periphery of flange 24. Ridge 48 can have the same height as ridge 43 to effect a continuous high pressure seal or it can have a lesser height where only a reduction in the thickness of folds 40 is desired. The number of score lines 16 utilized can vary with the thickness of the wall member and also with the radial dimension of flange 24. However, the number of score lines 16 will generally be sufficiently large so that the thickness, at the continuous annular high pressure seal area 42 of each fold 40, is less than twice the thickness of the wall of preform 21. It is also generally desirable that the radial dimension of flange 24 be sufficiently small and the number of score lines 16 be sufficiently great so that the bottom of the folds 40 at the inner edge of flange 24 do not extend downwardly below the plane of the bottom of gutter 46.

As illustrated in FIG. 1, it is generally preferred that score lines 16 be located completely within the portion of the wall member which forms the flange 24. This avoids the formation of pleats along the bottom portion of the vertical wall of the finished container. Such vertical pleats can increase the structural strength of the lower portion of the container, but are generally considered to be undesirable from an aesthetic viewpoint. The score lines 16 preferably terminate short of lower edge 13. This avoids interference between the scoring mechanism and cutting mechanism when the cutting and scoring operations are accomplished simultaneously. A score line 16 is preferably located adjacent the inner edge of the overlapped side margins to aid in the accommodation of the excessive material in this area. However, the overlapped side margins are preferably free of score lines 16 to avoid a fold 40 in the resulting double thickness portion of flange 24. The location of score lines 16 at equal intervals provides a greater degree of uniformity of the thickness of the resulting folds 40. The positioning of the score lines 16 parallel to the axis 23 in the unfolded preform 21 and radial to the axis 23 in the completed containers minimizes the length of the resulting folds, and also minimizes the possibilities of the formation of unsymmetrical folds. A score line can be provided along the imaginary line 17, ifdesired, to aid in accomplishing a uniform bend between the vertical wall of the container and the flange 24.

in one presently preferred container in accordance with the invention, the blank has a thickness of approximately 0.017 inch, a width of approximately 16 inches and a height of approximately 6% inches, and is provided with 28 score lines 16 equally spaced along the bottom edge of the blank. Each score line 16 is approximately five-sixteenths inch in length, which is just slightly shorter than the radial dimension of flange 24.

Reasonable variations and modifications are possible within the scope of the foregoing disclosure, the drawings and the appended claims to the invention.

[claims 1. A method of forming a container which comprises forming a preform having a substantially circular cross section and having an upper edge and a lower edge and having a plurality of score lines located in a lower marginal area adjacent said lower edge and extending generally perpendicularly toward said lower edge, said score lines being at least approximately uniformly spaced along the extent of said lower edge, positioning a bottom disc within the hollow of said preform adjacent said lower marginal area, bending said lower marginal area in wardly toward the axis of said preform and into contact with said bottom disc to form an inwardly directed radial flange, structurally bonding said bottom disc to said flange substantially throughout the area of contact therebetween, the bending of said lower marginal area inwardly causing the formation ofa fold along each of said score lines to accommodate the ex cessive material in said lower-marginal area due to the reduction in diameter thereof.

2. A process in accordance with claim 1 wherein said step of forming a preform comprises forming a generally rectangular blank having an upper edge and a lower edge and two side edges and having a plurality of score lines located in a lower marginal area adjacent said lower edge and extending generally perpendicularly toward said lower edge, said score lines being at least approximately uniformly spaced along the extent of said lower edge, convoluting said blank to overlap the side margins adjacent said side edges, and bonding the thus overlapped side margins to form a preform.

3. A method in accordance with claim 2 wherein said blank and said bottom disc are formed of paperboard having a coating on each side thereof of a synthetic thermoplastic polymeric material, the bonding of said overlapped side margins to each other and the bonding of said bottom disc to said flange being effected by thermal bonding of the contacting thermoplastic coatings.

4. A process in accordance with claim 3 further comprising crushing a continuous annular area of said flange to collapse said folds to form a liquid-tight seal between said flange and said bottom disc by means of said contacting thermoplastic coatings.

5. A process in accordance with claim 4 wherein the number of said score lines is sufficiently large so that the thickness at said continuous annular area of each said fold is less than twice the thickness of the wall of said preform, said overlapped side margins being free of said score lines.

6. A process in accordance with claim 5 further comprising forming an upwardly opening continuous annular gutter in the peripheral portion of said bottom disc and in the adjacent por tion of said flange, the radial dimension with respect to the axis of said preform of said gutter being less than the radial dimension of said flange, the number of said score lines being sufficiently great so that the bottom of said folds at said lower edge do not extend downwardly below the plane of the bottom of said gutter.

7. A process in accordance with claim 1 wherein said score lines are located completely within the portion of said preform which forms said flange, and wherein said score lines terminate short of said lower edge.

8. A process in accordance with claim 1 wherein the step of bending said lower marginal area inwardly comprises contacting said lower marginal area with an inwardly curved annular surface which is substantially coaxial with said preform with the apparent apex of said annular surface being remote from said preform to cause a simultaneous inwardly bending of said lower marginal area throughout the extent of said lower edge.

9. In a container comprising a wall member of substantially circular cross section having a lower portion thereof bent inwardly to form an inwardly directed radial flange, a bottom disc positioned within the hollow of said wall member and in contact with the upper surface of said flange, said disc being structurally bonded to said flange throughout at least a portion of the area of contact therebetween, the improvement comprising said lower portion of said wall member having a plurality of score lines preformed therein prior to the bending of said lower portion of said wall member to form said flange, said preformed score lines being substantially parallel to the axis of the substantially circular cross section of said wall member in the lower portion of said wall member prior to the ing a continuous annular area of said flange being crushed to collapse said folds in said area to form a liquid-tight seal between said flange and said bottom disc, the number of said score lines being sufficiently great so that the thickness at said continuous annular area of each said fold is less than twice the thickness of said wall member. 

1. A method of forming a container which comprises forming a preform having a substantially circular cross section and having an upper edge and a lower edge and having a plurality of score lines located in a lower marginal area adjacent said lower edge and extending generally perpendicularly toward said lower edge, said score lines being at least approximately uniformly spaced along the extent of said lower edge, positioning a bottom disc within the hollow of said preform adjacent said lower marginal area, bending said lower marginal area inwardly toward the axis of said preform and into contact with said bottom disc to form an inwardly directed radial flange, structurally bonding said bottom disc to said flange substantially throughout the area of contact therebetween, the bending of said lower marginal area inwardly causing the formation of a fold along each of said score lines to accommodate the excessive material in said lower marginal area due to the reduction in diameter thereof.
 2. A process in accordance with claim 1 wherein said step of forming a preform comprises forming a generally rectangular blank having an upper edge and a lower edge and two side edges and having a plurality of score lines located in a lower marginal area adjacent said lower edge and extending generally perpendicularly toward said lower edge, said score lines being at least approximately uniformly spaced along the extent of said lower edge, convoluting said blank to overlap the side margins adjacent said side edges, and bonding the thus overlapped side margins to form a preform.
 3. A method in accordance with claim 2 wherein said blank and said bottom disc are formed of paperboard having a coating on each side thereof of a synthetic thermoplastic polymeric material, the bonding of said overlapped side margins to each other and the bonding of said bottom disc to said flange being effected by thermal bonding of the contacting thermoplastic coatings.
 4. A process in accordance with claim 3 further comprising crushing a continuous annular area of said flange to collapse said folds to form a liquid-tight seal between said flange and said bottom disc by means of said contacting thermoplastic coatings.
 5. A process in accordance with claim 4 wherein the number of said score lines is sufficiently large so that the thickness at said continuous annular area of each said fold is less than twice the thickness of the wall of said preform, said overlapped side margins being free oF said score lines.
 6. A process in accordance with claim 5 further comprising forming an upwardly opening continuous annular gutter in the peripheral portion of said bottom disc and in the adjacent portion of said flange, the radial dimension with respect to the axis of said preform of said gutter being less than the radial dimension of said flange, the number of said score lines being sufficiently great so that the bottom of said folds at said lower edge do not extend downwardly below the plane of the bottom of said gutter.
 7. A process in accordance with claim 1 wherein said score lines are located completely within the portion of said preform which forms said flange, and wherein said score lines terminate short of said lower edge.
 8. A process in accordance with claim 1 wherein the step of bending said lower marginal area inwardly comprises contacting said lower marginal area with an inwardly curved annular surface which is substantially coaxial with said preform with the apparent apex of said annular surface being remote from said preform to cause a simultaneous inwardly bending of said lower marginal area throughout the extent of said lower edge.
 9. In a container comprising a wall member of substantially circular cross section having a lower portion thereof bent inwardly to form an inwardly directed radial flange, a bottom disc positioned within the hollow of said wall member and in contact with the upper surface of said flange, said disc being structurally bonded to said flange throughout at least a portion of the area of contact therebetween, the improvement comprising said lower portion of said wall member having a plurality of score lines preformed therein prior to the bending of said lower portion of said wall member to form said flange, said preformed score lines being substantially parallel to the axis of the substantially circular cross section of said wall member in the lower portion of said wall member prior to the bending of said lower portion of said wall member to form said flange and substantially radial to said axis in said flange, a fold being formed along each of said score lines in said flange to accommodate the excessive material in said lower portion due to the reduction in diameter thereof in the formation of said flange.
 10. A container in accordance with claim 9 further comprising a continuous annular area of said flange being crushed to collapse said folds in said area to form a liquid-tight seal between said flange and said bottom disc, the number of said score lines being sufficiently great so that the thickness at said continuous annular area of each said fold is less than twice the thickness of said wall member. 